So why are trans fats bad for us, and why do experts warn us to eat them at our own risk? Trans fats can have waist-widening and artery-clogging consequences.

Trans fats have been called “stealth fats” because this type of fat can be hidden in foods that you may regularly eat.

Reading food labels may not always protect you since gray areas in laws mean they might not be fully identified.

Here’s what you need to know about foods that contain trans fats.

What is Dietary Fat?

Dietary fats consist of different arrays of “fatty acids,” and these fatty acids are found in foods like animal products as well as plant foods like beans, nuts, seeds, and even (in very small amounts) vegetables.

Trans fats are a unique type of fat, and to understand trans fats, it’s helpful to learn a bit about the biochemistry of fat.

Fat, or fatty acids, differ based on their chemical structure. There are different types of saturated fats, such as palmitic acid and stearic acid found in animal products like meat, dairy, and some vegetable oils, like coconut and palm.

Unsaturated fatty acids, known as the “good” kind of fat, are divided into monounsaturated and polyunsaturated types, which differ in their chemical bond structure. These are found more predominantly in plant foods like olives, avocados, nuts, and seeds.

Many foods contain a range of fatty acids, both saturated and unsaturated. So while a steak is considered to be high in saturated fat, it also has a small amount of unsaturated fatty acids.

And while an olive contains mostly unsaturated fat, it also has small amounts of saturated fat. Foods are generally categorized by the type of fat that is the most prevalent, even if they contain a blend.

What’s the Difference Between Unsaturated, Saturated, and Trans Fats?

A fat’s chemical makeup affects its physical and culinary characteristics. Saturated fats are more solid at room temperature, whereas unsaturated fats are more liquid and thus more susceptible to going rancid faster.

That’s why you can open a bottle of sesame oil that’s been in the cupboard for too long and immediately notice that it smells “off.”

Enter trans fats, which were largely the invention of food manufacturers.

What are Trans Fats?

Trans fats are a certain type of fatty acid that has what is known as a “trans” chemical structure, which is basically a reconfiguration of the atoms.

Trans fats have been altered to be more like saturated fat — and therefore more solid at room temperature. Plus, they last longer before going rancid, saving money.

Trans fats do occur naturally in some foods, such as meat and milk products, but they entered the food system in a big way in the early 1900s, when the chemical process of hydrogenation was invented.

This new, chemically altered oil not only had beneficial cooking properties (like flakier pie crusts), it solved a major problem in the food industry. Baked and fried goods now had a longer shelf life.

Plus, it was cheap — but everything has a price.

Why Are Trans Fats Bad for You?

As research on hydrogenated vegetable oils accumulated, their downsides became apparent. Trans fats can increase LDL (“bad”) cholesterol, says James Marin, R.D., a dietitian based in Los Angeles, California.

Trans fat also lowers the “good” HDL cholesterol, whose function is to mop up excess fat lingering in the blood. Removing trans fats from your diet can promote heart health.

The U.S. Food and Drug Administration (FDA) followed suit in 2015, determining that partially hydrogenated oils, which were the primary source of artificial trans fats in processed foods, were no longer be considered safe for use in human food.

Why Do Some Foods Still Contain Trans Fats?

Trans fats were officially banned in 2015, but changes like that take time. “The problem is, trans fats are still found in foods even though the Food and Drug Administration took partially hydrogenated oils off the list of ingredients that are ‘generally recognized as safe’ back in 2015,” explains Krista Haynes, R.D., C.S.S.D., and nutrition manager at Beachbody. “The FDA gave food manufacturers until 2018 to comply with a ruling that all food prepared in the US must not include partially hydrogenated oils, unless approved by the FDA.”

So that’s why you still hear about these unhealthy fats — and why you still need to be on the lookout for them.

How to Find Hidden Trans Fats

The good news is that, theoretically, the Nutrition Facts label on most products will tell you whether a food contains trans fats or not.

The bad news is that the labels aren’t foolproof. Loopholes in government regulations mean that trans fat can still be in foods with a Nutrition Facts label that claims 0 g trans fat.

That’s because manufacturers are allowed to round amounts down, so a food that has 0.49 g trans fats per serving would say 0 g trans fats on the label. “Some food producers reduce serving sizes so that they can dupe the consumer into thinking it’s a healthy, trans-fat-free option,” says Haynes.

That means if a realistic portion size of that hidden source of trans fat is three servings (versus whatever the label claims you should consider to be a single serving), you could ingest 1.5 g of trans fats from a food that claims to contain zero.

To complicate efforts to avoid these fats, the FDA has made a special exception, allowing food companies to petition to use partially hydrogenated oils as additives and in other specific applications.

What About Natural Trans Fats?

Even if a food contains no partially hydrogenated oils, trans fats are still required to be listed on labels, because they are naturally found in food from some animals, such as cows and goats.

Would natural trans fats be a safer form than the chemically modified varieties? Maybe, but maybe not.

“Most of the research suggests that natural sources of trans fat may not hurt your health if consumed in small amounts,” says Haynes. “But if these foods are consumed in large amounts, then there may be negative cardiovascular effects similar to those from the man-made partially hydrogenated oils found in packaged and processed foods.”

That means you shouldn’t swap beef tallow or lard for shortening and margarine.

Common Foods High in Trans Fats

Ready to clear your diet of trans fats? Find out which common foods high in trans fats might be in your pantry or fridge right now.

Since the FDA started sounding warning bells about trans fats, food manufacturers and fast-food chains have voluntarily reduced their use of partially hydrogenated vegetable oils.

Where Do Trans Fats Hide in Foods?

Beyond the foods you know to contain trans fats, there are plenty more where partially hydrogenated fats lurk, including but not limited to:

Biscuits

Coffee creamer

Cream-filled candies

Creamy puddings

Crunchy Asian noodles

Frosting

Frozen burgers, beef sausages, and beef hot dogs

Granola bars

Ground beef

Ice cream

Meat jerky sticks

Microwavable meals like breakfast sandwiches or pastry tarts

Microwave popcorn

Packaged pancake batter

How to Avoid Trans Fats

Many of the traditional trans fat-filled foods, like margarine, reformulated their recipes and no longer contain them.

But be vigilant, advises Haynes: “Since your label may read ‘0 trans fats’ but still may contain them, always look at the ingredients list. If you read an ingredients label and see any type of hydrogenated vegetable oil or partially hydrogenated vegetable oil, that’s a red flag that trans fats are in that food.”

Nutrition

Nutrition

The information provided on this website (including the Blogs, Community pages, Program Materials and all other content) was originally intended for a US audience. Regulations in your country may vary.

+Results vary depending on starting point, goals and effort. Exercise and proper diet are necessary to achieve and maintain weight loss and muscle definition. The testimonials featured may have used more than one Beachbody product or extended the program to achieve their maximum results.

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

Consult your physician and follow all safety instructions before beginning any exercise program or using any supplement or meal replacement product, especially if you have any unique medical conditions or needs. The contents on our website are for informational purposes only, and are not intended to diagnose any medical condition, replace the advice of a healthcare professional, or provide any medical advice, diagnosis, or treatment.

Apple logo, Apple TV, App Store, iPad, iPhone, and iPod touch are registered trademarks of Apple Inc. Roku is a registered trademark of Roku, Inc. in the United States and other countries. Amazon, Kindle, Fire, and all related logos are trademarks of Amazon.com or its affiliates. Chrome, Chromecast, and the Chrome logo are trademarks of Google Inc.